A passengers train travels from reno to Las Vegas a distance of 706 km in 6.5 h. what is the change average speed?
1 answer:
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Answer:
(A) 4.09 kg/s
(B) 589.9 m/s
(C) 0.0008707 m^{3} = 8.71 cm^{2}
Explanation:
inlet pressure of steam (P1) = 4 MPa
inlet temperature of steam (T1) = 400 degree celcius
inlet velocity (V1) = 60 m/s
outlet pressure (P2) = 2 MPa
outlet temperature (T2) = 300 degree celcius
inlet area (A1) = 50 cm^{2} = 0.005 m^{2}
rate of heat loss (Q) = 75 kJ/s
(A) mass flow rate (m) = \frac{A1 x V1}{α1}
where the initial specific volume (α1) for the given temperature and pressure is gotten from tables A-6 = 0.07343 m^3/kg
m = \frac{0.005 x 60}{0.07343}
m = 4.09 kg/s
(B) we can get the outlet velocity using the energy balance equation
E in = E out
m(h1 + \frac{(V1)^{2}}{2}) = m(h2 + \frac{(V2)^{2}}{2})
V2 =
where h1 and h2 are the enthalpies and are gotten from table A-6
V2 =
V2 = 589.9 m/s
(C) the outlet area is gotten from mass flow rate (m) = \frac{A2 x V2}{α}
A2 = (α2 x m) / V2
where the initial specific volume (α2) for the given temperature and pressure is gotten from tables A-6 = 0.12552 m^3/kg
A2 = (0.12552 x 4.09) / 589.5 = 0.0008707 m^{3} = 8.71 cm^{2}
<u>Answer: The model is described by :</u>
The strength of the field increases as you get closer to Earth, as shown by the smaller spaces between the circles.
Explanation :
According to universal gravitational law, the force acting in the universe between two objects is given by :
It is clear that the gravitational force depends directly on the product of masses and inversely on the square of the distance between them.
The given image shows a model of the gravitational field around Earth. The arrows in the image show the direction of the force. Gravitational field depends on the position of objects.
As we move closer to the earth, the force increases and hence the field increase.
So, the correct option is (D) " The strength of the field increases as you get closer to Earth, as shown by the smaller spaces between the circles ".